Wireless communications systems have changed the way that their users work and enjoy information access. No longer are users of wireless broadband access systems restricted to specific locations with wireline access to information services. In fact, users are free to move wherever they like within a coverage area and still have rapid access to information that they need and/or desire.
Currently available wireless communications system utilize a single identifier, usually an Internet Protocol (IP) address, to identify a communications device as well as to address (route information to and from) the communications device. The use of a single identifier may complicate device mobility since as the communications device moves about, it may be necessary to handover the communications device from a first access network to a second access network, thereby potentially resulting in a different identifier. The use of the different identifier may complicate locating the communications device.
A variety of newly proposed protocols, such as Host Identity Protocol (HIP) defined by the Internet Engineering Task Force (IETF), separate the single identifier into two identifiers, with a host identifier (e.g., a host identity) to be used for network session identification, and an IP address for addressing purposes. In addition to simplifying locating a communications device, the use of two identifiers may also provide better security support, as well as a framework with which a mechanism for mobility management may be designed.
However, supporting the dual identifier protocols, such as HIP, may require modifications to the IP protocol stack at hosts (also commonly referred to as communications devices, mobiles, mobile stations, terminals, users, subscribers, and so on). Requiring upgrades to hosts may be an expensive (if not impossible) proposition. A HIP proxy (or equivalently, a HIP proxy server) provides HIP function including security features by the network without requiring modifications to the host, yet it is still necessary to design the appropriate mobility management mechanisms that will improve the handover performance.
Additionally, existing mobility support mechanisms with the dual identifier protocols, such as HIP, suffer from long handover delay due to signaling overhead, such as duplicate address detection (DAD), location update, security signaling, and so forth.
Therefore, there is a need for a system and method for providing mobility management in a wireless communications system without requiring upgrades to hosts, i.e., provides support for legacy hosts.